Ford 5R55 Buyer's Guide: 5R55N, 5R55W and 5R55S
Which Explorer, Mountaineer, Mustang, Aviator and Thunderbird use which 5R55, why the servo bores wear, and what a replacement needs.
A 2002–2010 Explorer that flares between gears, slips into 3rd or loses 5th usually has a 5R55W or 5R55S behind the engine. Very often the damage is a groove worn into the case, not a burned clutch.
Ford built the 5R55 in several versions over about fifteen years. The letters matter when you order one.
Which version do you have
The **5R55E** is the older family, found in
Explorers and Rangers of the late 1990s and early 2000s; its smaller sibling, the 5R44E, went behind lighter engines. The **5R55N** started in the Lincoln LS and Jaguar S-Type sedans and moved to the Thunderbird for 2002.
Then came the **5R55W**, with the 2002 redesign of the
Explorer and Mountaineer. The **5R55S** is the later version, in the 2005–2010 Mustang and the 2003–2005 Lincoln Aviator. Later Explorers got it too.
For 2006,
Ford moved the 4.6-liter V8 Explorer and Mountaineer to a six-speed, the 6R60. The V6 trucks kept the 5R55S. Parts listings disagree about which Lincoln LS and Thunderbird years got which letter, so send us the VIN and skip the chart.
The servo bore problem
All three later versions hold two of their gears with bands, and each band is applied by a servo. A steel pin carries the servo's push through a bore in the aluminum case, and over miles the pin wears that bore oval. Apply oil leaks past, so the band gets less pressure than it should.
You feel it as a flare on the 1–2, 2–3 or 4–5 shift, then as lost gears. A parts maker that sells bronze sleeve kits for exactly these bores also lists codes P0732, P0733 and P0735 and burned band lining. Left long enough, the case itself is ruined.
A band adjustment doesn't fix a worn bore. It keeps leaking.
Other failures by version
On the **5R55N**, a damaged intermediate sprag gives a bind in 3rd and 4th, or no 3rd and 4th at all, according to the ATRA seminar notes. The same notes give the N's failsafe gears as 4th and 2nd, with Reverse. A car stuck in one gear with harsh engagement is usually an electrical fault.
On the **4R/5R44E and 5R55E** trucks of 1995–2002, the classic complaint was low line pressure at wide-open throttle. The ATRA notes list missing 2nd or 3rd and slipping shifts, sometimes with code P1762. Ford answered with a revised separator plate and a pressure-relief plug. On a heavily contaminated unit the valve body got replaced as well.
A few 2001 S-
Type owners had a different complaint: the car wouldn't come out of Park on a hill. The ATRA fix was a Ford part, the rooster comb, swapped for the Jaguar one.
What a replacement needs
Start with the servo bores. Ask whether they've been sleeved or at least measured; a remanufacturer that sleeves them will tell you so.
Then the letter. The N, W and S don't interchange, and a V6 Explorer's unit isn't a Mustang's. We match by VIN.
At installation, the cooler is machine-flushed and flow-tested or replaced, and the invoice shows which, because band material goes everywhere the fluid does. The invoice should also carry the fluid type and quantity, plus any module programming or adaptive reset the vehicle calls for.
Expedia Protection covers personal-use units for 5 years with unlimited miles. An Explorer doing fleet work, or towing and plowing commercially, falls under the manufacturer's commercial term instead, typically 18 months or 75,000 miles. And get a written pre-authorization number from us before anyone pulls a unit over a warranty concern.
A used 5R55W from a salvage yard comes with whatever the bore wear was on the day that truck parked. [Our reman-vs-used comparison](/blog/reman-vs-used-engines-transmissions-how-to-choose) walks through that tradeoff.
Related on Expedia Parts
- Warranty policy and Expedia Protection: /warranty
- Pre-authorization before removing the unit: /blog/pre-authorization-before-removing-unit
- When your transmission needs a reflash: /blog/when-transmission-needs-reflash
- Transmission slip and shudder after replacement: /blog/transmission-slip-and-shudder-after-replacement
- Valve body issue or software issue: /blog/valve-body-issue-or-software-issue
